Generally, a semiconductor die may be connected to other devices external to the semiconductor die through a type of packaging utilizing external connections. The external connections may be formed by initially forming a layer of underbump metallization in electrical connection with a contact pad on the semiconductor die and then placing additional conductive material onto the underbump metallization. In between the underbump metallization and the contact pad may be a passivation layer that is used to protect and support the structures of the semiconductor die. Once in place, the additional conductive material may be placed into physical contact with the external device and then the semiconductor device may be bonded to the external device. In such a fashion, a physical and electrical connection may be made between the semiconductor die and an external device, such as a printed circuit board, another semiconductor die, or the like.
However, the material that comprises the underbump metallization, the passivation layer, and the contact pad are different types of materials that are formed with different processes and are manufactured on top of one another and may include very different types of materials, such as dielectric materials, metallization materials, etch stop materials, barrier layer materials, and other materials utilized in the formation of the semiconductor die. Each one of these different materials has unique properties different from each other that can cause significant stresses to be applied to the materials in each of the layers. If not controlled, these stresses can cause cracks to form, for example, within the passivation layer between the contact pad and the underbump metallization. Such cracks can damage or even destroy the semiconductor die during the manufacturing process or else during its intended use.
Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated. The figures are drawn to clearly illustrate the relevant aspects of the embodiments and are not necessarily drawn to scale.